Multi-carrier incremental redundancy for packet-based wireless communications

ABSTRACT

In a particular embodiment, a method of providing redundancy for error recovery in multi-carrier wireless communications includes transmitting a primary version of information via a first carrier, transmitting a first portion of a redundancy version of the information via a second carrier, and transmitting a second portion of the redundancy version of the information via a third carrier. The primary version is encoded using a first encoding scheme and the redundancy version is encoded using a second encoding scheme. The primary version, the first portion, and the second portion are transmitted substantially simultaneously.

CLAIM OF PRIORITY

This application for patent is a Divisional Application of Ser. No.11/238,791 filed Sep. 28, 2005, entitled “Multi-Carrier IncrementalRedundancy for Packet-Based Wireless Communications,” which claimspriority to U.S. Provisional Application No. 60/615,254 filed Oct. 1,2004, entitled “Multi-Carrier Incremental Redundancy for GERAN,” andassigned to the assignee hereof and hereby expressly incorporated byreference herein.

REFERENCE TO CO-PENDING APPLICATION FOR PATENT

This Application also claims priority to co-pending Divisionalapplication Ser. No. 12/703,440, filed Feb. 10, 2010, entitled“Multi-Carrier Incremental Redundancy for Packet-Based WirelessCommunications”.

BACKGROUND

1. Field

The present invention generally pertains to the field of wirelesscommunications, and more particularly to the field of error recovery inwireless communication systems.

2. Background

Over the past two decades, cellular telephones have become increasinglycommonplace. During this same period, a number of advances in wirelesstechnology have afforded cellular telephones with more features, betterreception, higher bandwidth and increased system capacity. Today'sdigital and packet-based wireless systems are considerably more advancedthan the first digital wireless systems, and show great promise for thefuture. GSM (Global System for Mobile Communications) was among thefirst widespread digital wireless systems. GSM was introduced as asecond generation (2G) wireless system throughout Europe in the early1990s and is now operational in over 100 countries worldwide. Over theyears the developers of GSM introduced a number of enhancements andimprovements, building on the basic voice services of GSM to add variousdata and speech capabilities to the system. With these improvements GSMhas evolved into a system capable of offering a number of enhanceddigital mobile voice and data telephony services such as Internetaccess, multimedia and video.

The GSM enhancements include GPRS, EDGE and GERAN. GPRS, the GeneralPacket Radio Service first introduced in the mid 1990s, is a TDMAwireless packet-based network architecture based on GSM. GPRS is basedon the GSM air interface (i.e., the interface between the terminal andthe base station) and on the GSM air interface structure of timeslotsand TDMA frames. GPRS offers increased bandwidth to users, and moreefficient use of bandwidth for operators in as many slots as may bedynamically allocated between voice and data depending upon the demandconditions. This allows a GPRS link to use from one to eight of theslots available per GSM frame, at up to 22.8 kb/s for each time slot.Further, the number of slots for the GPRS up-link and down-link may beallocated independent of each other. GPRS employs four different codingschemes, CS1 through CS4, each of which is a phase modulation codingscheme using Gaussian minimal shift keying (GMSK) modulation. GPRSsupports X.25, the low speed packet transmission protocol popular inEurope. GPRS was implemented as a step towards implementing the EDGEsystem (Enhanced Data for GSM Evolution). EDGE is an enhancement to GPRSwhich uses the same spectrum allocations as existing GSM systems (e.g.GSM900, GSM1800 and GSM1900). EDGE features nine coding schemes, fouremploying GMSK modulation and five employing Eight Phase Shift Keying(8PSK) modulation. The four EDGE GMSK coding schemes, MCS1 through MCS4,are akin to the four GPRS coding schemes (i.e., CS1 through CS4). Theother five EDGE coding schemes, MCS5 through MCS9, use 8PSK modulation,producing a three-bit word for every change in carrier phase. The use of8PSK modulation roughly triples the GPRS peak data rates. Anotherenhancement to GSM, GERAN (GSM Edge Radio Access Network) supports theEDGE network as an alternative radio access network compatible with the3G GSM-evolved Core Network (CN). The GERAN architecture allowsconnection to the A, Gb and Iu interfaces of the CN. GERAN is beingimplemented to deliver packet-based real time wireless servicesincluding speech, multimedia, video and Internet access.

Despite the improvements in coding schemes and enhanced features, fromtime to time, errors occur in wireless systems due to poor receptionconditions. To recover from reception errors, EDGE, and the enhancementsand services associated with it, provide an incremental redundancy errorrecovery scheme. When a transmission fails due to the detection of anerror, the mobile receiver sends an automatic repeat request (ARQ) backto the base station. In response to the ARQ, the base station transmitsthe failed transmission using a different encoding scheme. Errorrecovery is performed by combining the initial message with the secondversion of the message retransmitted using a different encoding scheme.This conventional system of error recovery increases the likelihood ofrecovering a failed message, but results in delays due to the ARQ beingsent back to the source of the message with a request to retransmitanother version encoded differently.

SUMMARY

In one embodiment, a method of providing redundancy for error recoveryin multi-carrier wireless communications is provided. The methodcomprises encoding a primary version of information to be transmittedwith a first encoding scheme and encoding a redundancy version of theinformation to be transmitted with a second encoding scheme. The methodfurther comprises transmitting the primary version of the informationencoded with the first encoding scheme, the primary version beingtransmitted on a first carrier, and transmitting the redundancy versionof the information encoded with the second encoding scheme. At leastpart of the redundancy version is transmitted on a second carrier. Theredundancy version is transmitted in response to transmitting theprimary version of the information within a same transmission timeperiod as the primary version.

In another embodiment, a communication device for providing redundancyfor error recovery in multi-carrier wireless communications is provided.The device comprises an encoder for encoding a primary version ofinformation to be transmitted with a first encoding scheme and forencoding a redundancy version of the information to be transmitted witha second encoding scheme. The device further comprises a transmitter fortransmitting the primary version of the information encoded with thefirst encoding scheme, the primary version being transmitted on a firstcarrier, and for transmitting the redundancy version of the informationencoded with the second encoding scheme. At least part of the redundancyversion is transmitted on a second carrier. The redundancy version istransmitted in response to transmitting the primary version of theinformation within a same transmission time period as the primaryversion.

In another embodiment, an apparatus for providing redundancy for errorrecovery in multi-carrier wireless communications is provided. Theapparatus comprises means for encoding a primary version of informationto be transmitted with a first encoding scheme and means for encoding aredundancy version of the information to be transmitted with a secondencoding scheme. The apparatus further comprises means for transmittingthe primary version of the information encoded with the first encodingscheme, the primary version being transmitted on a first carrier, andmeans for transmitting the redundancy version of the information encodedwith the second encoding scheme. At least part of the redundancy versionis transmitted on a second carrier. The redundancy version istransmitted in response to transmitting the primary version of theinformation within a same transmission time period as the primaryversion.

In another embodiment, a computer readable media embodying a method forerror recovery in multi-carrier wireless communications is provided. Themethod comprises encoding a primary version of information to betransmitted with a first encoding scheme and encoding a redundancyversion of the information to be transmitted with a second encodingscheme. The method further comprises transmitting the primary version ofthe information encoded with the first encoding scheme, the primaryversion being transmitted on a first carrier, and transmitting theredundancy version of the information encoded with the second encodingscheme. At least part of the redundancy version is transmitted on asecond carrier. The redundancy version is transmitted in response totransmitting the primary version of the information within a sametransmission time period as the primary version.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute partof the specification, illustrate various embodiments of the invention.

FIG. 1A depicts a wireless network architecture that supports mobilestations and client devices in accordance with at least one embodiment;

FIG. 1B depicts details of a base station and a wireless mobile unit ina wireless network;

FIG. 2A depicts an RLC/MAC block of information being allocated into aGSM structure of timeslots and frames;

FIG. 2B illustrates an exemplary incremental redundancy scheme;

FIG. 3 depicts a radio block being transmitted via a multi-carriertransmission system in accordance with at least one embodiment;

FIG. 4 is a multi-carrier system implementing an incremental redundancyscheme in accordance with at least one embodiment;

FIG. 5 depicts incremental redundancy in accordance with at least oneembodiment in EDGE with variable time-frequency spreading;

FIG. 6 depicts a multi-carrier, multi-redundancy in accordance with atleast one embodiment which provides redundancy for error recoverypurposes;

FIG. 7 depicts a method of setting up the initial parameters forpracticing at least one embodiment;

FIG. 8 depicts a method to provide error recovery for wirelesscommunication systems in accordance with at least one embodiment; and

FIG. 9 depicts a block diagram of a method of decoding and combiningredundancy versions according to at least one embodiment.

DETAILED DESCRIPTION

FIG. 1A depicts a typical wireless network architecture that supportsmobile stations and client devices in accordance with variousembodiments. FIG. 1A is a block diagram which illustrates components ofa typical wireless network 110 and its interrelation with the elementsof an exemplary embodiment. Downstream from the network 130, a wirelesssystem typically has three broad categories of components: the corenetwork controllers (SGSN 102), the base stations (BSC/BTS 104) andwireless mobile units 120. Although the network controller in the figureis labeled as a Serving GPRS Support Node (SGSN) 102, in someimplementations it may take other forms or be called other names, forexample, a mobile switching center (MSC). Generally, an SGSN is the corenetwork entity dealing with packet-switched connections, while the MSCis the core network entity dealing with circuit-switched connections.Similarly, the figure depicts base station controllers/base transceiverstation (BSC/BTS) 104 which may sometimes take other forms or bereferred to by other names, for example base station system (BSS).Mobile units 120 are known by many different names, for example,cellular telephones, mobile stations, wireless handsets, pocket bells,etc. The scope of the invention covers these other terms, e.g., MSC,BSS, and the like.

The wireless network shown is merely exemplary and may include anysystem that allows communication with mobile wireless devices, such asmobile units 120 that communicate over-the-air between and among eachother and/or between and among components connected via a wirelessnetwork 110. Such mobile units 120 include without limitation one ormore cellular telephone 112, PDA (personal digital assistant) 114, pager116, navigation device 118, wirelessly connected computer 128, music orvideo content download unit 122, wireless gaming device 124, inventoryunit 126, or other like types of wireless devices. Cellular or otherwireless telecommunication services may communicate with a carriernetwork through a data link or other network link via the fixed network130 which may be the PSTN (public switched telephone network), ISDN, theInternet, a LAN, WAN, or other such network. Signaling between SGSN 102and the fixed network 130 may be performed using Signaling System Number7 (SS7) protocol. SS7 is used for trunk signaling in ISDN and widelyused in current public networks.

The wireless network 110 controls messages or other information,typically sent as data packets, sent to a SGSN 102. Each SGSN 102 isgenerally connected to one or more BSC/BTS 104. The SGSN 102 acts withinthe wireless network 110 in a manner akin to a normal switching node ofa landline network (e.g., PSTN or ISDN). SGSN 102 includes the logic,for example in a processor 106, to manage and control the mobile units120. The processor 106 or other logic manages and controls functionssuch as call routing, registration, authentication, location updating,handovers and/or encoding schemes for the mobile units 120 registered atthe BSC/BTS 104 base stations associated with the SGSN 102. Anotherpiece of a typical wireless network is the Operations and MaintenanceCenter (OMC), which may be considered part of the processor 106 or otherlogic. The OMC organizes the operation and setup of the wirelessnetwork.

In a similar manner to the network 130, the SGSN 102 is connected to anumber of BSC/BTS 104 by a network configured for data transfer and/orvoice information. In this way, within the wireless network 110,communications to and from various SGSNs 102 and BSC/BTSs 104 typicallyuse a network of landlines, the Internet and/or a public switchedtelephone network (PSTN). The base station subsystem, including BSC/BTS104, controls the radio link with the mobile units 120. Within the basestation subsystem, BSC/BTS 104 has one or more transmitters andreceivers to send and receive information to/from mobile units 120.BSC/BTS 104 broadcasts data messages or other information wirelessly tothe mobile units 120, such as cellular telephone 112, by over-the-air(OTA) methods. The BSC/BTS 104 communicates with mobile units 120 acrossthe Um interface, also known as the air interface or radio link. FIG. 1Bdepicts details of a BSC/BTS 104 and a wireless mobile 120. Each basestation BSC/BTS 104 includes an encoder/decoder 105 whichencodes/decodes information in the protocol or encoding scheme fortransmission/reception. The base station BSC/BTS 104 also includes aprocessor 101 capable of performing or controlling routines andprocesses involved in wireless communications, and may also beconfigured to include a memory 103 for storing the various protocols,routines, processes or software to be used in conducting wirelesscommunications. For example, the memory 103 may store one or moretransmission strategies for communicating with various mobile units 120.The transmission strategies include information concerning the number ofredundancy versions to be sent, the timing for transmitting theredundancy version (or versions) relative to the primary version, andany encoding schemes or protocols to be used for the transmission andreception of wireless communications. This information may also bestored in a memory 108 of the SGSN 102, and communicated to the basestation BSC/BTS 104 as needed. Embodiments of the mobile units 120, ascan be seen in the detail of cellular telephone 112 shown in FIG. 1B,may be configured to include a processor 107, memory 109 andencoder/decoder 111 which perform functions similar to the correspondingparts of the BSC/BTS 104. Mobile units 120 may also have an antenna 113,a receiver section 115 and other electronics known to those of ordinaryskill in the art for wirelessly receiving information which may entailmonitoring for, and receiving, transmissions sent simultaneously oroverlapping on different carriers in a multi-carrier wireless system.

The wireless network 110 includes at least one Home Location Register(HLR) and a number of Visitor Location Registers (VLRs) (not shown)which provide information for call-routing and roaming. The HLR,typically centralized within wireless network 110, contains theadministrative information for each mobile unit 120 registered in thewireless network 110, along with the current location of the mobile unit120. The HLR could be implemented as a distributed database, althoughthere is logically only one HLR per network. Each SGSN 102 of thewireless network 110 has associated with it a Visitor Location Register(VLR) stored in the memory 108 of the SGSN/MSC 102. The VLR storesselected administrative information from the centralized HLR for use incall control and the provisioning of the subscriber services for eachmobile unit 120 currently under control of the SGSN/MSC 102. There aregenerally two other registers used for authentication and security in awireless network 110, an Equipment Identity Register (EIR) and anAuthentication Center (AuC). The EIR is a database of all valid mobileunits 120 associated with the network. The mobile units 120 areidentified within the EIR by their unique International Mobile EquipmentIdentity (IMEI). The AuC contains copies of the secret key stored ineach mobile unit 120 for use in authentication and encryption over theradio channel. It should be noted that the SGSN/MSC 102 itself does notcontain the information about particular mobile units 120. The mobileunit 120 information is typically stored within the HLR and VLRs.

Mobile units 120 are generally equipped with a Subscriber IdentityModule (SIM), a smart card that identifies the mobile unit 120 enablingit to make and receive calls at that terminal and receive othersubscribed services. The IMEI of the wireless unit 120 stored on the SIMcard uniquely identifies that particular mobile unit 120. The SIM cardalso has stored on it an International Mobile Subscriber Identity (IMSI)used to identify the subscriber to the system, along with a copy of thesecret key from the AuC register for authentication, and otherinformation pertaining to security, identification and communicationprotocols. Each mobile unit 120 has installed on it, or otherwisedownloads, one or more software applications, such as games, news, stockmonitors, and the like. The mobile unit 120 includes logic which may beconfigured in the form of one or more processing circuits executingresident configured logic, microprocessors, digital signal processors(DSPs), microcontrollers, or other like combination of hardware,software and/or firmware containing processors and logic configured toat least perform the operations described herein.

The wireless communication between each of the mobile units 120 and theBSC/BTS 104 may be based on any of several different technologies, suchas CDMA (code division multiple access), TDMA, FDMA (frequency divisionmultiplexed access), OFDM (orthogonal frequency division multiplexing)and any systems using a hybrid of coding technologies such as GSM, orother like wireless protocols used in communications or data networks,so long as the system or protocol provides simultaneous multi-channel(e.g., multi-carrier) communications. A carrier may be thought of as aparticular frequency (or frequency band) at a given point in time. Theconcept of a channel encompasses a carrier, but may be more broadlythought of to include spatial diversity (e.g., different communicationlinks) or other like type of communication paths which may besimultaneously received by a receiver. Data communication typicallytakes place between the mobile unit 120, BSC/BTS 104 and SGSN 102. TheSGSN 102 may be connected to multiple data networks such as a carriernetwork, PSTN, the Internet, a virtual private network, and the like,thus allowing the client device access to a broader communicationnetwork. As discussed in the foregoing, in addition to voicetransmission, data may be transmitted to the client device via SMS orother OTA methods known in the art.

FIG. 2A depicts an RLC/MAC block of information being allocated into astructure of timeslots and frames. GSM is used herein as an exemplarysystem to explain the RLC/MAC concepts and frame structure. Embodimentsof the invention may be incorporated in other wireless systems as well.GSM allocates its available radio spectrum using such a scheme whichcombines aspects of TDMA (Time Division Multiple Access) and FDMA(Frequency Division Multiple Access). GSM uses FDMA concepts to divideits available bandwidth carrier frequencies spaced 200 kHz apart.Typically, each base station has several of these carrier frequenciesassigned to it. Time division, a TDMA concept, is achieved in GSM byhaving each of the carrier frequencies divided into timeslots 205 asshown in FIG. 2A. GSM timeslots last 15/26 ms (0.577 ms). The terms“timeslots” and “burst periods” may be used interchangeably. There areeight 0.577 ms timeslots 205 in each GSM TDMA frame 207 lasting 4.615ms. A GSM physical channel may be thought of as one timeslot 205 perTDMA frame 207. For example, a physical channel could consist of thetimeslot “0” (205) in each of the sequence of TDMA frames “x” through“x+3” (207) shown in FIG. 2A. A wireless link on a channel may occupythe same timeslot 205 (e.g., timeslot 0) within each of a series of TDMAframes 207, for the duration of the link or at least until a new channelis assigned. Channels may either be dedicated channels allocated to aparticular mobile station for a call, or may be common channels used bya number of mobile stations in idle mode on an as-needed basis.

In the GSM system, the framing scheme may be set up in different waysaccording to the function being carried out. One such channel is fullrate GSM traffic channels (TCH). TCH carry speech and data traffic andmay be grouped in multiframes consisting of 26 frames. That is, each TCHmultiframe includes 26 TDMA frames. (Multiframes may be defined tocontain different numbers of frames aside from 26 frames; e.g., 52 framemultiframes.) Each 26-frame multiframe is 120 ms long (120 ms/26=4.615ms=one frame). Hence, one multiframe (120 ms) divided by 26 framesdivided by eight burst periods per frame, is equal to one burst period(timeslot) of approximately 0.577 ms. The 26 frames in a GSM multiframeinclude 24 traffic frames, one frame dedicated to the Slow AssociatedControl Channel (SACCH), and another frame which, at the present time,remains undefined and is not used. In order to afford some time betweenwhen a mobile station is transmitting and when it is receiving, uplinkTCHs and downlink TCHs are separated in time by three burst periods. Inaddition to full-rate TCHs (TCH/F), there are half-rate TCHs (TCH/H).There are also eighth rate TCHs, sometimes called Stand-alone DedicatedControl Channels (SDCCH), which are used mainly for transmittinglocation updating information. The use of half-rate TCHs effectivelydoubles the system capacity as compared to communications usingfull-rate THCs since TCH/H speech coding is performed at 7 kbps ratherthan 13 kbps for full rate TCH/F.

FIG. 2A shows an RLC/MAC 201 block mapped onto one radio block 203 andthen onto four timeslots 205 belonging to four sequential TDMA frames207 of a GSM multiframe. The Layer 2 transmission protocol of GPRS/EDGEis RLC/MAC. RLC (Radio Link Control) is a sublayer of the radiointerface that provides reliability, and MAC (Medium Access Control) isthe lower of the two sublayers of the Data Link Layer and handles accessto a shared medium. RLC/MAC provides the control and coordinationnecessary for GPRS wireless communications. In GPRS, one RLC/MAC 201block is transmitted as part of one radio block 203. The radio block 203is sent via four consecutive GPRS timeslots 205, which are transmittedon a GPRS timeslot multiframe, for example, a 24 timeslot multiframe asdescribed above or possibly a 52 timeslot multiframe. The inter-timeslotdistance between each of the four timeslots 205 containing the radioblock is eight timeslots, or the length of one TDMA frame 207. Thecontent of the four timeslots 205 is simply the sequence of the fourportions of the RLC/MAC 201 block itself. Since GPRS does not provideany incremental redundancy for error recovery, there is no incrementalredundancy relationship among the four timeslots 205, and they do notcontain any redundant information of the radio block data 203. However,an incremental redundancy scheme is provided in EDGE in which redundancyversions are sent at different points in time on the same carrier.

FIG. 2B illustrates an exemplary incremental redundancy scheme.Incremental Redundancy may be employed in EDGE within the RLC/MACprotocol, at Layer 2. If no errors are detected in an RLC/MAC block thatis sent to a mobile station, the RLC/MAC block is passed to the nextlayer for processing. For example, if no errors had been detected in thefirst transmission 211 of FIG. 2B (an RLC/MAC block encoded with MCS-6)it would have been passed to the next layer with no retransmissions, andretransmission blocks 213 and 215 would not have been sent. In thepresent EDGE implementation, for a negatively acknowledged RLC/MAC blockin which an error is detected the mobile sends an automatic repeatrequest (ARQ) back to the base station. In response to the ARQ, the basestation retransmits the RLC/MAC block using a different MCS (Modulationand Coding Scheme). The retransmitted block(s) are typically recombinedwith the first block, thus enhancing the redundancy and increasing thechances of recovering the RLC/MAC block free of errors. This situationis depicted in FIG. 2B assuming an error was detected in the firsttransmission block 211 resulting in an ARQ being sent back to the basestation. In response to the ARQ the same information was sent again inretransmission blocks 213 and 215, this time encoded in MCS-3. Since adifferent modulation and coding scheme was used for the retransmission(MCS-3) versus the first transmission (MCS-6), it took tworetransmission blocks instead of one to communicate the data. Theretransmission, in this example, used the first retransmission part 213and the second retransmission part 215 to communicate the data.

Most embodiments of the invention encode the redundancy versions using adifferent encoding scheme (e.g., a different MCS) than that of theprimary version. This provides incremental redundancy rather than merelyproviding redundancy by sending redundant versions encoded in the samescheme. However, some embodiments of the invention may encode theredundancy version using the same MCS if it is likely that errors arosedue to reception conditions associated with a particular carrier.Conventional implementations of EDGE do not retransmit a negativelyacknowledged RLC/MAC block using the same MCS as the originaltransmission because errors caused by prevailing adverse conditions ofthe air interface would most likely produce a similar result containingerrors since conventional implementations of EDGE send redundancyversions using the same carrier as the primary version.

When a different MCS is employed for redundancy versions, there are someconstraints regarding the choice of encoding schemes. MCS coding schemesare categorized within families (e.g., family A, B or C). If a differentMCS is used for a redundancy version, it should be chosen from the same“family” of the MCS used in the first transmission. For example, FIG. 2Bdepicts a negatively acknowledged MCS-6 RLC/MAC block 211 beingretransmitted using two MCS-3 blocks 213 and 215. This is appropriatesince MCS-6 and MCS-3 both belong to Family A. Additionally, when alower MCS is used, the retransmitted RLC/MAC blocks may need more radioblocks than the first transmission since the same information is to beretransmitted with a lower code rate. This is depicted in FIG. 2B, whichshows that the first transmission 211 being sent with MCS-6 in one radioblock needs two radio blocks 213 and 215 due to the retransmission beingperformed with MCS-3.

As shown in FIG. 2B, the interval between the first MCS-6 transmission211 and the first MCS-3 transmission 213 is larger than the intervalbetween the two MCS-3 transmissions 213 and 215. In a conventionalincremental redundancy implementation for EDGE, which sends theredundancy versions on the same carrier, this time interval beforetransmission of the redundancy version is due to the negativeacknowledgement process in EDGE; e.g., an ARQ being sent back to thebase station. The negative acknowledgement process in EDGE is RLC-basedand therefore relatively time-consuming. Following the failure of thefirst transmission 211 in a conventional EDGE incremental redundancyimplementation, an acknowledgement signal (not shown) needs to be sentback to the sender before beginning the retransmissions. The duration ofthis interval is implementation-dependent and is based on the RLC/MACsettings. Embodiments of the invention are not limited in this way,since there is not necessarily a requirement for an ARQ. Instead, theredundancy versions are transmitted as part of a predefined scheme(e.g., in response to the primary version be transmitted, encoded orotherwise processed) rather than being sent in response to the ARQ. Insome embodiments, the redundancy version may be sent according to apredefined transmission strategy within the same transmission timeperiod as the primary version, but not necessarily at the same time. Forthe purposes of timing the transmissions of primary and redundancyversions, a transmission time period is defined herein as any time afterthe transmission of the primary version begins up until the start of thenext primary version, assuming the next primary version is not delayeddue to a reception error. In other embodiments, the transmission timeperiod may be defined as a predefined value that is less than the timeit takes an ARQ signal to be received back at the transmitter followinga reception error. A transmission strategy is defined as a predefinedplan for the number of redundancy versions to be sent, the timing forsending the redundancy version(s) relative to the primary version, andthe encoding schemes to be used for the primary version and the one ormore redundancy versions. While some embodiments send redundancyversions following the primary version but within the same transmissiontime period as the primary version, other embodiments send theredundancy versions simultaneous to the primary version, as discussed inconjunction with FIGS. 3-4 and 6.

FIG. 3 depicts a radio block 303 being transmitted via a multi-carriertransmission system in accordance with the invention. This figure istypical of embodiments of the present invention which include enhancedincremental redundancy error recovery for GERAN or other wirelesssystems based on a multi-carrier architecture and on the introduction ofOFDM (orthogonal frequency division multiplexing). A number ofmulti-carrier wireless transmission systems exist which may be used withthe invention, including various formats of multi-carrier CDMA, spreadspectrum communications systems, or OFDM. Other such communicationsystems may be used so long as they are characterized by the use ofsimultaneous multiple channels; e.g., multi-carrier systems such asMulti-Carrier GPRS (MC-GPRS). The invention allows such multi-channel(e.g., multi-carrier) architectures to be exploited to realizeimprovements in the transmission structure, for instance, to improve theMC-GPRS transmission structure. An embodiment is depicted in FIG. 3showing an RLC/MAC block 301 being mapped onto one radio block 303 andthen onto four timeslots 305-311 belonging to four parallel TDMA framesin four parallel carriers. A mobile terminal is able to receive theradio block 303 by monitoring all four carriers as it awaits thetransmission of the RLC/MAC block.

In an EDGE system, every radio block is sent on a different frequency(frequency hopping system), but terminals in conventional EDGEimplementations are required to monitor only one frequency at any givenpoint in time.

In accordance with the invention, radio blocks may be wirelesslytransmitted via a multi-carrier transmission system to the reducedtransmission time, since a radio block may be transmitted in a singleduration, e.g., a single timeslot group of closely spaced or contiguoustimeslots. Accordingly, the transmission time for a given amount of datausing embodiments of the invention is considerably faster than that ofthe conventional GPRS transmission structure depicted in FIG. 2A.Comparing the embodiment shown in FIG. 3 with that depicted in FIG. 2A,a radio block in the multi-carrier system may be transmitted in parallelover several carriers as illustrated in FIG. 3. In contrast, theconventional system spreads the radio block over the duration of threeTDMA frames (actually, three TDMA frames plus one timeslot, or 25timeslots) as illustrated in FIG. 2A. Further, using embodiments of theinvention the peak transmission rate may be quadrupled in themulti-carrier system since four carriers are used in parallel in thisexample, as opposed to the use of a single carrier in the GPRStransmission structure of FIG. 2A.

The implementation of multi-carrier transmission for radio blocks istransparent with respect to the upper layers in as much as embodimentsof the invention do not impact SNDCP (sub network dependent convergenceprotocol), LLC (logical link control) and the RLC (radio link control)transmission parameters (e.g., window, etc.). However, the MAC (mediumaccess control) may be affected by the embodiments using multi-carriertransmission. The timeslot and timing structure of the GSM air interfacedoes not need to be modified. Hence, the multi-carrier redundancyimprovement embodiments may be easier to introduce than a simplemulti-carrier option where four RLC/MAC streams are sent in parallel onfour parallel carriers, with each of these streams still beingtransmitted in GSM according to a GPRS protocol, for example, GPRS R99.Using four parallel RLC/MAC streams per GPRS R99 introduces morecomplications to the RLC protocol, as the four streams could result inunpredictable behaviors for the window size and the sequence numberspace at the receiver side.

Incremental redundancy schemes according to at least some embodimentsmay be implemented by transmitting different redundancy versions of thesame information block. By combining the different versions, thereceiver may improve the probability of error recovery for correctreception. The various redundancy versions may differ in the modulation,coding or puncturing scheme. However, redundancy versions and theprimary transmission, or primary version, are typically chosen from thesame family of coding schemes. By way of explanation, MCS coding schemesare categorized within families (e.g., Family A (MCS-3, MCS-6 andMCS-9); Family B (MCS-2, MCS-5 and MCS-7); and Family C (MCS-1 andMCS-4)). The primary version and the redundancy versions should belongto the same MCS “family.” For example, if the primary transmission iscoded as MCS-7, a Family B coding scheme, the redundancy versions shouldalso belong to Family B; e.g., MCS-2 or MCS-5.

FIG. 4 depicts a multi-carrier system implementing a redundancy schemeaccording to at least some embodiments of the invention. As shown in thefigure, a multi-carrier architecture allows a different technique to beemployed for the transmission of the different redundancy versions oneach of the carriers. This enables various redundancy versions to besent simultaneously using different carriers; e.g., differentfrequencies. Alternatively, in some embodiments, the various redundancyversions may be sent at nearly the same time, but not necessarilysimultaneously. For example, the various redundancy versions may be sentwithin the same transmission time period (i.e., at any time after thetransmission of the primary version begins up until the start of thenext primary version). In some implementations (e.g., some embodimentsin a GSM system), a transmission time period may be equal to the timeduration of a frame.

The data block 401 is encoded in three different redundancy versions,403, 405 and 407. As shown in FIG. 4, each of the three differentredundancy versions 403-407 is transmitted on its own respective carrier409-413 in parallel, that is, at approximately the same time. Althougheach of versions 409-413 is labeled in the figure as a “redundancyversion,” logically one of them may be considered the “primary version”with the other two being considered redundancy versions of the primaryversion. Other embodiments may encode any number of different redundancyversions to be sent simultaneously or at least within the sametransmission time period, e.g., two redundancy versions, three, four,etc.

Errors in wireless transmission due to fading tend to correlate toparticular frequencies for a given set of circumstances. Fading overwireless links tends to be frequency-selective, so differenttransmissions sent on different carriers will likely experiencedifferent amounts of attenuation. Use of embodiments to simultaneouslysend multiple redundancy versions over different carriers provides forfrequency diversity in the multi-carrier system of FIG. 4, instead ofmerely providing time diversity, as per the conventional system of FIG.2B. In some situations, errors may be more likely to occur in aparticular frequency range due to fading. In accordance with alternativeembodiments of the invention, if the primary version is being sent at afrequency known to be prone to fading, a redundancy version sent at afrequency not prone to fading may be encoded with the same coding schemeas the primary version (e.g., primary version subject to fading=MCS-6and redundancy version not subject to fading=MCS-6 also). Thisembodiment runs contrary to the general rule-of-thumb of encoding theredundancy versions using differing coding schemes from the same family.Since the coding of different redundancy versions is the same, thisembodiment is considered to merely provide redundancy rather thanincremental redundancy.

A multi-carrier incremental redundancy scheme according to the inventionmay be implemented in any of several embodiments tailored to suit theparticular needs of an operator, or even tailored to suit a givensituation. For example, using self decodable redundancy versions enablevarious embodiments to be implemented using either selection combining,soft combining, or selective soft combining. Selection combining is theprocess of having the receiver use only the one redundancy version thathas been selected for use. Soft combining is the process of combiningall the transmitted/received redundancy versions, using a statisticalalgorithm or other means, for use in error recovery. Selective softcombining is when some redundancy versions are combined while others arediscarded. The choice of which redundancy version(s) to use may beimplemented according to prearranged decision making rules. One suchrule is to select the first redundancy version for combining (if anerror was initially detected) and then error check the transmittedinformation. The first redundancy version (i.e., the first version to bedecoded) could for example be sent on an anchor carrier, the anchorcarrier being the main carrier of a multi-carrier structure. If an erroris still detected, then the first two redundancy versions are combinedwith the primary version, and another round of error checking iscompleted. Further redundancy versions are added as needed (and asavailable), so long as errors continue to be detected. A receiver may beconfigured with the logic to implement one or more of selectioncombining, soft combining or selective soft combining, depending uponthe circumstances and parameters affecting the transmission/reception;e.g., carrier-to-interference ratio (C/I), air interfacecharacteristics, noise conditions, atmospheric or other interferenceconditions, jamming, allowable transmission power, or other likecircumstances and parameters affecting the signal reception (ortransmission at the other end). The decision may be based on themeasured C/I or other parameters affecting a particular one or more ofthe carriers. The decision of whether to use selection combining, softcombining or selective soft combining may be affected solely by analgorithm, a measurement or logic within the receiver. Alternatively,the decision may be controlled at the transmitter end and communicatedto the receiver, or may be controlled at any intermediate point; e.g.,BSC/BTS, SGSN/MSC, within the PSTN, or other intermediate point betweenthe two ends of the overall communication link.

FIG. 5 depicts incremental redundancy according to at least oneembodiment of the invention in EDGE with variable time-frequencyspreading. In conventional implementations of the EDGE system, aretransmission of the same information block due to an error takes adifferent time duration for the actual transmission itself than that ofthe original transmission whenever a different MCS coding scheme ischosen for the retransmission. For example, the transmission time of thefirst transmission 211 at (MCS-6) (shown in FIG. 2B) is shorter induration than that of the sum of the first and second retransmissions213 and 215 (at MCS-3), which contain the same amount of informationencoded with a different encoding scheme. Embodiments of the presentinvention may overcome this disadvantage. Accordingly, after a firsttransmission performed with one MCS-6 radio block 501, theretransmission with two MCS-3 radio blocks may be performed within atime duration no greater in length than the first transmission.

As shown in FIG. 5, embodiments of the present invention may exploit amulti-carrier architecture by sending the redundancy versions via twoMCS-3 retransmissions, first retransmission part 503 and secondretransmission part 505, using two separate carriers, carrier n+2 andcarrier n+1, respectively. Rather than taking a longer time duration forthe actual transmission of the redundancy versions, embodiments of thepresent invention use multiple carriers to send 503 and 505 in parallel.The mapping of MCS to number/location of carriers may either beprearranged or determined by an algorithm, or may be specified in alook-up table.

As is evident from FIG. 5, the two retransmitted blocks 503 and 505 maybe transmitted and received in parallel. For implementations in which itis not known at the terminal whether the transmission will take placeover one carrier, or two or more carriers, the mobile terminalpreferably monitors the parallel carriers continuously. For example, amobile terminal may monitor the two or more carriers on which theretransmission will be sent in addition to monitoring the originalcarrier. Having the mobile terminal monitor the parallel carrierscontinuously allows embodiments of the invention to avoid the need foran out-of-band control channel (as is required in HSDPA or 1×EV-DV)indicating when transmissions and retransmissions are to take place.However, in alternative embodiments of the invention, an out-of-bandcontrol channel may be used to provide carrier mapping for theredundancy versions, or the mapping could be encoded as part of a firstsent redundancy version (or portion thereof) for all subsequentredundancy transmissions.

FIG. 6 depicts a multi-carrier, multi-redundancy embodiment, whichprovides redundancy for error recovery purposes. In the example shown,the primary version 601 containing information encoded using MCS-6 issent in parallel with two other MCS-3 transmissions 603 and 605containing the same information which serve as the redundancy versionfor the primary version 601. Other encoding schemes besides MCS-3 andMCS-6 may be used, as is known to those of ordinary skill in the art.The embodiment depicted in the figure may be used to provide incrementalredundancy for EDGE or for other like wireless services or systems. Suchembodiments are configured to exploit the multi-carrier architecture bytransmitting different redundancy versions simultaneously and inparallel over different carriers. In EDGE systems, backwardcompatibility is achieved by maintaining the same RLC/MAC architectureas is used in GSM, that is, blocks belonging to the same “family” aresent in parallel. In this embodiment, the various redundancy versionsmay be transmitted via a different number of carriers in a multi-carrierwireless system. For example, as discussed above, the same amount ofinformation in the form of different redundancy versions may be sentwith one MCS-9 radio block, two MCS-6 radio blocks, and four MCS-3 radioblocks—thus entailing the use of one, two, and four parallel carriers,respectively. MCS-9, MCS-6 and MCS-3 are from the same family and have a1-2-4 code rate relationship. Alternatively, redundancy versions may beencoded from different MCS families, so long as bit stuffing is used tooffset the differing block size of separate MCS families.

A receiver according to embodiments of the invention may perform any ofselection combining, soft combining, or hard and soft combining. Forexample, the case where the same information is sent with MCS-6 andMCS-3 entails the transmission of three parallel radio blocks over threecarriers: one for MCS-6 and two for the two MCS-3 radio blocks. Here,twice as many MCS-3 radio blocks are needed since the code rate ishalved. A receiver may exploit this multi-carrier architecture as longas it receives a subset of the transmitted blocks, for example, if anytwo blocks out of the transmitted three are received.

Embodiments of the present invention allow for reduced latency,increased peak rate, and improved coverage. Since the receiver mayperform combining of the blocks sent in parallel over the multiplecarriers, the same performance may be achieved with a lower C/I sincethe instantaneous code rate is smaller. In general, to fully exploit thecapability of EDGE high values of C/I are needed.

FIG. 7 depicts a method of setting up the initial parameters forpracticing at least one embodiment of the invention. The method beginsat 701, and proceeds to 703 for the selection of a modulation and codingscheme for the primary version of the information and redundancyversions. For example, a message to be transmitted using the EDGE airinterface may use 8PSK modulation and be encoded in the MSC-6 codingscheme. In this example, the corresponding redundancy versions couldthen be MCS-3 encoded using GMSK modulation. However, the invention isnot limited to these examples and other combinations of encoding schemesknown by those of ordinary skill in the art may be used with theinvention. Further, the modulation and coding scheme do not necessarilyneed to be selected each time a message is transmitted. Instead, adefault modulation and coding scheme may be used, or a predefinedmodulation and coding scheme for a given set of circumstances. Forinstances in which the coding scheme is being selected, either as adefault scheme or for a particular communication, it is appropriate totailor the encoding scheme selection to the prevailing conditions. Forexample, if the reception conditions are very good, a minimal impactredundancy scheme may be selected (i.e., the redundancy scheme whichtakes up the least resources may be determined to be appropriate). Onthe other hand, if reception conditions are poor and error rates arerunning at relatively high levels, a more robust redundancy scheme maybe selected, which is likely to use relatively more resources as atradeoff for providing better error recovery capabilities. For example,one incremental redundancy plan which provides very robust results is toencode the primary version of the information as one MCS-9 transmission,and have the first redundancy version consist of two MCS-6 transmissionsand a second redundancy version consisting of four MCS-3 transmissions.Two separate redundancy versions encoded in different formats, inaddition to the initial message (primary version), provide very gooderror recovery capabilities.

Once the coding scheme has been selected in block 703, the methodproceeds to 705 where a transmission strategy is determined. The termtransmission strategy is used herein to include the relative timing forsending the various transmissions/retransmissions. For example, theprimary version of the information could be sent first (e.g., 501 ofFIG. 5), and one or more redundancy versions simultaneously sent at alater time (e.g., 503 and 505 of FIG. 5). In at least one embodiment, asecond redundancy version is sent. This may be done at the same time thefirst redundancy version is sent (e.g., same time period as 503 and505), or may be performed at a later time. Alternatively, all versions(e.g., the primary version and all redundancy versions) may be sent atthe same time (e.g., FIG. 4 or FIG. 6). In at least one embodiment ofthe invention the transmission strategy may be predetermined so that thereceiver knows when and where to monitor a second carrier, orsimultaneously monitor two or more carriers, in order to receive theredundancy versions. Having the transmission strategy prearranged avoidsthe need for out-of-band signaling as is required in conventionalsystems.

The selection of a coding scheme in block 703 and prearrangingtransmission strategy in block 705 may affect each other, and may beperformed either in tandem or in any order. For example, it may bepossible to select a transmission strategy (705) before choosing acoding scheme (703). These activities may be performed during an initialstep-up stage or provisioning period and set as a default condition. Thechoice of a coding scheme and transmission strategy may be lateraltered, as needed, to better adapt to current conditions; e.g.,reception conditions, communication traffic patterns and schedules,revenue considerations, as well as various other like types ofconditions such as the timing and quality considerations dependent uponvarious types of content. For instance, the transmission of voice needsreal-time error recovery (or very small delays for error recovery)versus content in which minor delays may be acceptable such as Internetbrowsing or email applications.

Once the coding schemes and transmission strategies have been selected,the method proceeds to 707 for the selection of any other communicationprotocols, as are known by those of ordinary skill in the art. Suchprotocols may include the parameters used in provisioning variousnetwork equipment (e.g., SGSN 102, BSC/BTS 104 and/or mobile units 120of FIG. 1A), or parameters needed to set up or tear down communicationslinks. Once the communication protocols have been selected in block 707,the method proceeds to 709 where it is completed. In 709 the variousparameters, which were selected in 701 through 707, may be stored forfuture use, and communicated to those portions of the system whereneeded. The parameters may be stored in memory 108 of the SGSN 102 shownin FIG. 1A, or elsewhere within the system.

FIG. 8 depicts a method for practicing at least one embodiment of theinvention to provide error recovery for wireless communication systems.In block 801, the initial parameters are set up as explained above inconjunction with FIG. 7. Once the initial parameters have been set up,the method proceeds to 803 where it is determined whether there isinformation to be transmitted. If there is no information to betransmitted, the method proceeds according to the “NO” branch from 803to block 805 to wait for a message, and then loops back to 803 to againdetermine whether there is a message to be transmitted. In block 803, ifit is determined that there is information to be transmitted, the methodproceeds according to the “YES” branch from 803 to 807 to encode theinformation to be transmitted. In some embodiments, even if it has beendetermined that there is information to be transmitted and the methodhas proceeded to block 807 or further for processing the information,the system also continues to monitor for additional messages to betransmitted in accordance with block 805. That is, some steps forprocessing messages to be transmitted may be handled in parallel as thesystem continues to monitor for new messages to be transmitted in block805. In block 807, the message is encoded according to the protocolspreviously defined in the initialization phase, as depicted in FIG. 7.

In one exemplary embodiment, the primary version of the message may beencoded using one MCS-9 transmission. Once the primary version of themessage has been encoded, the method proceeds to 809 to encode one ormore redundancy versions. For example, given the exemplary embodimentusing one MCS-9 block for the primary version of the information, afirst redundancy version may consist of two MCS-6 transmissions alongwith a second redundancy version of four MCS-3 transmissions. It shouldbe noted that most embodiments described herein involve actions taken tohandle the redundancy versions (blocks 809-815) in response to theprimary version being obtained and encoded, not in response to receivingany sort of out-of-band signal to send a redundancy version. Aredundancy version is considered to be transmitted in response to thetransmission of the primary version when, as a result of obtaining theinformation to send in block 803 the system encodes one or moreredundancy versions for transmission. This is evident, for example, fromFIG. 4 in which all versions are sent simultaneously. In embodiments inwhich the redundancy versions are not sent simultaneously with theprimary version, but are sent within the same transmission time period(i.e., at a time after the primary version transmission begins up untilthe start of the next primary version) the redundancy versions are sentin response to transmission of the primary version. In someimplementations (e.g., some embodiments in a GSM system), a transmissiontime period will be equal to the time duration of a frame. Once theredundancy versions have been encoded the method proceeds to block 811.

In block 811 the carriers may be selected in accordance with thecommunication scheme being used, or to conform to the protocols orspecifications of the system. Once the carriers for the primary versionand the one or more redundancy versions have been selected, the methodproceeds to 813 where the various versions are transmitted, eithersimultaneously or in some staggered manner, for example, as per theexemplary embodiments discussed in conjunction with FIGS. 3-6. Asdiscussed above, the transmission of the redundancy versions may beperformed in response to the primary version being transmitted, not inresponse to receiving any sort of out-of-band signal with information ofa data failure or instructions to send a redundancy version. Thetransmission of the primary version and redundancy version(s) typicallytakes place from a stationary base station (e.g., BSC/BTS 104 of FIG.1A) to a mobile unit (e.g., 120). Hence, blocks 801-813 typically takeplace in a stationary BTS or SGSN, while block 815 (and the blocks ofFIG. 9) typically occur in a mobile unit. However, in some embodimentsthe mobile unit may transmit a primary version and one or moreredundancy versions. The message transmissions taking place in block 813may be a single transmission (e.g., SMS message) or may be one of anumber of transmissions (e.g., a bit of speech being transmitted as partof an on-going telephone conversation). For each primary transmissionand the associated redundancy versions, the transmission of block 813may be followed by block 815 for decoding the various transmissions, andcombining them if an error is detected. The various embodiments may useany of selection combining, soft combining, and/or selective softcombining, depending upon the scheme being implemented and prevailingreception conditions. Once the transmissions have been decoded andcombined to produce a combined version of the received transmissions,the method proceeds to block 817. In an alternative embodiment, block817 is performed only once (or not at all) before the communication linkis torn down. In some embodiments or in certain situations block 817 isnot performed, and instead the method proceeds directly from block 815to 805.

In 817, it is determined whether conditions exist to warrant changes orupdates to the redundancy scheme, or aspect of it. For example, if aredundancy scheme is in place which calls for only one redundancyversion and the error rate is still at an unacceptably high level, theconditions may warrant changing the redundancy scheme to transmit two ormore redundancy versions associated with the primary version. Anotherexample of an alteration to the redundancy scheme may come in the formof changing the method of combining the redundancy versions. Forexample, if the redundancy scheme in place uses selection combining, butthe error rate is higher than a predetermined threshold, then the schememay be changed to soft combining or selective soft combining, in aneffort to provide better error recovery if the prevailing air interfaceconditions are preventing error recovery. Block 817 may involve changingcarriers to avoid interference and/or transmission errors due to fading,which may be correlated to particular frequencies in a given set ofconditions. Since different transmissions sent on different carriers maybe subject to varying amounts of attenuation, a change in carrierfrequency may improve the error recovery results. Further, block 817 mayinclude any changes made due to new versions of software, downloadedpatches, updates to incorporate modifications to telecom specifications,or other like types of periodic maintenance to the system. Uponcompletion of 817 and once any changes or updates to the redundancyscheme have been implemented, the method proceeds back to 805 to waitfor the next message to be transmitted.

FIG. 9 depicts a block diagram for a method of decoding and combiningredundancy versions according to at least one embodiment. Typicallythese activities take place in a mobile unit or other receiver in whichembodiments of the invention are implemented. The blocks depicted inFIG. 9 provide some detail about decoding, combining and error recoverythat may take place in the block 815 of the previous figure. The methodbegins in block 901 where an error check is performed to determinewhether the primary version of the transmitted information containserrors. The error check may involve any sort of routine or algorithmspecified by the system, the system operator, or conducted within themobile unit itself. For example, the error detection may involve aredundancy check such as checksum, a cyclical redundancy check (CRC), aframe check sequence (FCS), or error correction codes (ECC) such asHamming codes, Reed-Solomon code, Reed-Muller code, Binary Golay code,convolutional code, turbo code, or other like type of error detection ordetection/correction scheme. These, or other like routines known tothose of ordinary skill in the art, may be used in an error recoveryscheme. Different types of actions may be taken in block 901 toascertain whether there are errors such as making a channel measurementor received power measurement, a positive or a negative ACK, an implicitestimate of mobile unit reception quality, or any other like type ofroutine or test for errors in reception known to those of ordinary skillin the art. Alternatively, if the reception conditions are known to bebelow a predetermined level, a received transmission may be assumed tocontain errors for the purpose of utilizing the redundancy versionstransmitted in accordance with embodiments of the invention until suchtime as reception conditions are known to improve. Upon completion oferror detection in block 901, the method proceeds to the decision block903. If no error is detected in the transmission, the method proceedsfrom block 903 to block 905 in accordance with the “NO” branch to waitfor another transmission and then loops back to block 901. In someembodiments, a default condition may be specified in which one or moreof the redundancy versions are combined with the primary version (the“YES” branch) regardless of whether or not errors have been detected. Inthe event an error is detected, the method proceeds from block 903 toblock 907 in accordance with the “YES” branch for determination ofwhether selection combining is to be performed.

The method of error recovery may be predetermined to default toselection combining, selective soft combining, soft combining, or acombination of these error recovery routines. Alternatively, the type oferror recovery may be varied or otherwise selected to best suit theconditions, depending upon the reception conditions, prevailing trafficconditions, economics or other like parameters for selecting a type oferror recovery. In any event, at block 907 if selection combining is tobe used the method proceeds in accordance with the “YES” branch to block909 where a redundancy version of the message is selected for use inerror recovery. If, at block 907, it is determined that selectioncombining is not to be used for error recovery, the method proceeds from907 to 911 where it is determined whether selective soft combining is tobe used. If, at block 911, it is determined that selective softcombining is to be used for error recovery the method proceeds from 911to 913 via the “YES” branch for the selection and soft combining of oneor more redundancy versions so that selective soft combining errorrecovery may be performed. If selective soft combining is not to beused, the method proceeds from block 911 to block 915 in accordance withthe “NO” branch. If it is determined that selection combining (907) andselective soft combining (911) are not to be used, in accordance withblock 915 the available redundancy versions may be soft combined for usein error recovery.

Once one of the error recovery techniques have been chosen (e.g.,selection combining, selective soft combining, soft combining, or otherlike error recovery technique), the method proceeds to block 917 and theselected redundancy version, or the soft-combination of the selectedredundancy versions, are decoded. Once the aforementioned process iscompleted the method proceeds to 919 for an error recovery routine.Block 919 may entail similar activities to those performed in errorchecking the primary version in block 901 (or block 815 of the previousfigure). In some embodiments, if the error recovery of block 919 fails,the method loops back to 901 for further processing of the data. This isdepicted as a dotted line between 919 and 901. For example, in a firstpass selection combining may have been chosen (or prearranged) inaccordance with block 907. On a second pass, in block 907 a secondredundancy version could be combined with the primary version and thefirst redundancy version, or alternately, soft combining (915) orselective combining (911) may be selected on the second or subsequentpasses.

The figures are provided to explain and enable the invention and toillustrate the principles of the invention. Some of the activities forpracticing the invention shown in the method block diagrams of thefigures may be performed in an order other than that shown in thefigures. For example, in FIG. 8 the selection of the carriers (811) maytake place before encoding the redundancy versions (809). Further, thoseof ordinary skill in the art understand that information and signals maybe represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Those of ordinary skilled in the art will also appreciate that thevarious illustrative logical blocks, modules, circuits, and algorithmroutines described in connection with the embodiments disclosed hereinmay be implemented as electronic hardware, computer software, firmware,or combinations thereof. To clearly illustrate this interchangeabilityof hardware and software, various illustrative components, blocks,modules, circuits, and steps have been described above generally interms of their functionality. Whether such functionality is implementedas hardware or software depends upon the particular application anddesign constraints imposed on the overall system. Practitioners ofordinary skill in the art will know to implement the describedfunctionality in varying ways for each particular application, but suchimplementation decisions should not be interpreted as causing adeparture from the scope of the present invention.

The various illustrative logical blocks, modules, and circuits describedin connection with the embodiments disclosed herein may be implementedor performed with a general purpose processor, a digital signalprocessor (DSP), an application specific integrated circuit (ASIC), afield programmable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, computer or state machine. A processor mayalso be implemented as a combination of computing devices, e.g., acombination of a DSP and a microprocessor, a plurality ofmicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other such configuration.

The activities of methods, routines or algorithms described inconnection with the embodiments disclosed herein may be embodieddirectly in hardware, in a software module executed by a processor, orin a combination of the two. A software module may reside in RAM memory,flash memory, ROM memory, EPROM memory, EEPROM memory, registers, harddisk, a removable disk, a CD-ROM, or any other form of storage mediumknown in the art. An exemplary storage medium is coupled to theprocessor in such a manner that the processor may read information from,and write information to, the storage medium. In the alternative, thestorage medium may be integral to the processor. The processor and thestorage medium may reside in an ASIC. The ASIC may reside in a userterminal. In the alternative, the processor and the storage medium mayreside as discrete components in a user terminal.

Various modifications to the illustrated and discussed embodiments willbe readily apparent to those of ordinary skill in the art, and theprinciples defined herein may be applied to other embodiments withoutdeparting from the spirit or scope of the invention. Thus, the presentinvention is not intended to be limited to the embodiments shown hereinbut is to be accorded the widest scope consistent with the principlesand novel features disclosed herein.

In describing various embodiments of the invention, specific terminologyhas been used for the purpose of illustration and the sake of clarity.However, the invention is not intended to be limited to the specificterminology so selected. It is intended that each specific term includesequivalents known to those of skill in the art as well as all technicalequivalents which operate in a similar manner to accomplish a similarpurpose. Hence, the description is not intended to limit the invention.The invention is intended to be protected broadly within the scope ofthe appended claims.

The invention claimed is:
 1. A method of providing redundancy for errorrecovery in multi-carrier wireless communications, the methodcomprising: transmitting a primary version of information via a firstcarrier; transmitting a first portion of a redundancy version of theinformation via a second carrier; and transmitting a second portion ofthe redundancy version of the information via a third carrier; whereinthe primary version is encoded using a first encoding scheme and theredundancy version is encoded using a second encoding scheme and whereinthe primary version, the first portion, and the second portion aretransmitted substantially simultaneously; wherein decoding the primaryversion, the first portion and the second portion are configured to bedecoded upon reception, wherein the first portion is configured to becombined with the primary version, with the second portion, or with theprimary version and the second portion based on a combination scheme;wherein the combination scheme comprises selective soft combining andwherein the primary version, the first portion, or the second portion isfurther configured to be discarded without being combined.
 2. The methodof claim 1, wherein the first encoding scheme and the second encodingscheme belong to a single encoding scheme family.
 3. The method of claim1, wherein the first encoding scheme is based on Modulation and CodingScheme-6 (MCS-6) and the second encoding scheme is based on Modulationand Coding Scheme-3 (MCS-3).
 4. The method of claim 1, wherein the firstencoding scheme and the second encoding scheme belong to differentencoding scheme families.
 5. The method of claim 4, further comprisingbit stuffing the redundancy version to offset a block size differencebetween the primary version and the redundancy version.
 6. The method ofclaim 1, wherein the first portion of the redundancy version comprises afirst plurality of portions of the redundancy version that aretransmitted via a first plurality of carriers, and wherein the secondportion of the redundancy version comprises a second plurality of otherportions of the redundancy version that are transmitted via a secondplurality of carriers.
 7. The method of claim 1, further comprisingselecting a transmission strategy at least partially based on a datareception condition indication of a transmission, the data receptioncondition indication received from a mobile device.
 8. The method ofclaim 7, wherein the transmission strategy specifies at least one of anumber of redundancy versions to be transmitted, timing information forsending the redundancy version relative to the primary version, andcoding schemes for encoding the primary version and the redundancyversion.
 9. An apparatus for providing redundancy for error recovery inmulti-carrier wireless communications, the apparatus comprising: meansfor generating a primary version of information for transmission via afirst carrier; means for generating a first portion of a redundancyversion of the information for transmission via a second carrier; meansfor generating a second portion of the redundancy version of theinformation for transmission via a third carrier, wherein the primaryversion, the first portion, and the second portion are transmittedsubstantially simultaneously; and means for encoding the primary versionusing a first encoding scheme and encoding the redundancy version usinga second encoding scheme; wherein decoding the primary version, thefirst portion and the second portion are configured to be decoded uponreception, wherein the first portion is configured to be combined withthe primary version, with the second portion, or with the primaryversion and the second portion based on a combination scheme; whereinthe combination scheme comprises selective soft combining and whereinthe primary version, the first portion, or the second portion is furtherconfigured to be discarded without being combined.
 10. The apparatus ofclaim 9, further comprising means for transmitting the primary version,the first portion, and the second portion.
 11. The apparatus of claim 9,wherein the first encoding scheme and the second encoding scheme belongto a single encoding scheme family.
 12. The apparatus of claim 9,wherein the first encoding scheme and the second encoding scheme belongto different encoding scheme families.
 13. The apparatus of claim 9,wherein the first portion of the redundancy version comprises a firstplurality of portions of the redundancy version that are transmitted viaa first plurality of carriers, wherein the second portion of theredundancy version comprises a second plurality of other portions of theredundancy version that are transmitted via a second plurality ofcarriers.
 14. The apparatus of claim 9, further comprising means forselecting a transmission strategy at least partially based on a datareception condition indication of a transmission, the data receptioncondition indication received from a mobile device.
 15. The apparatus ofclaim 14, wherein the transmission strategy specifies at least one of anumber of redundancy versions to be transmitted, timing information forsending the redundancy version relative to the primary version, andcoding schemes for encoding the primary version and the redundancyversion.
 16. A communication device for providing redundancy for errorrecovery in multi-carrier wireless communications, the communicationdevice comprising: a processor configured to generate a primary versionof information for transmission via a first carrier, to generate a firstportion of a redundancy version of the information for transmission viaa second carrier, and to generate a second portion of the redundancyversion of the information for transmission via a third carrier, whereinthe primary version, the first portion, and the second portion aretransmitted substantially simultaneously; and an encoder configured toencode the primary version using a first encoding scheme and to encodethe redundancy version using a second encoding scheme; wherein decodingthe primary version, the first portion and the second portion areconfigured to be decoded upon reception, wherein the first portion isconfigured to be combined with the primary version, with the secondportion, or with the primary version and the second portion based on acombination scheme; wherein the combination scheme comprises selectivesoft combining and wherein the primary version, the first portion, orthe second portion is further configured to be discarded without beingcombined.
 17. The communication device of claim 16, wherein the firstencoding scheme and the second encoding scheme belong to a singleencoding scheme family.
 18. The communication device of claim 16,wherein the first encoding scheme and the second encoding scheme belongto different encoding scheme families.
 19. The communication device ofclaim 16, wherein the first portion of the redundancy version comprisesa first plurality of portions of the redundancy version that aretransmitted via a first plurality of carriers, wherein the secondportion of the redundancy version comprises a second plurality of otherportions of the redundancy version that are transmitted via a secondplurality of carriers.
 20. The communication device of claim 16, whereinthe processor is further configured to select a transmission strategy atleast partially based on a data reception condition indication of atransmission, the data reception condition indication received from amobile device.
 21. The communication device of claim 20, wherein thetransmission strategy specifies at least one of a number of redundancyversions to be transmitted, timing information for sending theredundancy version relative to the primary version, and coding schemesfor encoding the primary version and the redundancy version.
 22. Acomputer program product for providing redundancy for error recovery inmulti-carrier wireless communications, the computer program productcomprising: a non-transitory computer readable medium comprising: codefor causing a computer to generate a primary version of information fortransmission via a first carrier; code for causing the computer togenerate a first portion of a redundancy version of the information fortransmission via a second carrier; code for causing the computer togenerate a second portion of the redundancy version of the informationfor transmission via a third carrier, wherein the primary version, thefirst portion, and the second portion are to be transmittedsubstantially simultaneously; and code for causing the computer toencode the primary version using a first encoding scheme and to encodethe redundancy version using a second encoding scheme; wherein decodingthe primary version, the first portion and the second portion areconfigured to be decoded upon reception, wherein the first portion isconfigured to be combined with the primary version, with the secondportion, or with the primary version and the second portion based on acombination scheme; wherein the combination scheme comprises selectivesoft combining and wherein the primary version, the first portion, orthe second portion is further configured to be discarded without beingcombined.
 23. The computer program product of claim 22, furthercomprising code for causing a transmitter to transmit the primaryversion, the first portion, and the second portion.
 24. The computerprogram product of claim 22, wherein the first encoding scheme and thesecond encoding scheme belong to a single encoding scheme family. 25.The computer program product of claim 22, wherein the first encodingscheme and the second encoding scheme belong to different encodingscheme families.
 26. A method of providing redundancy for error recoveryin multi-carrier wireless communications, the method comprising:transmitting a primary version of information via a first carrier;transmitting a first portion of a redundancy version of the informationvia a second carrier; and transmitting a second portion of theredundancy version of the information via a third carrier; wherein theprimary version is encoded using a first encoding scheme and theredundancy version is encoded using a second encoding scheme, whereinthe first portion of the redundancy version and the second portion ofthe redundancy version are transmitted after transmission of the primaryversion is completed, and wherein the first portion of the redundancyversion and the second portion of the redundancy version are transmittedsubstantially simultaneously; wherein decoding the primary version, thefirst portion and the second portion are configured to be decoded uponreception, wherein the first portion is configured to be combined withthe primary version, with the second portion, or with the primaryversion and the second portion based on a combination scheme; whereinthe combination scheme comprises selective soft combining and whereinthe primary version, the first portion, or the second portion is furtherconfigured to be discarded without being combined.
 27. The method ofclaim 26, wherein the first portion of the redundancy version and thesecond portion of the redundancy version are transmitted in response totransmitting the primary version.
 28. The method of claim 26, furthercomprising transmitting a carrier mapping for the first portion of theredundancy version and for the second portion of the redundancy versionvia an out-of-band control channel.
 29. The method of claim 26, furthercomprising encoding a carrier mapping for the first portion of theredundancy version and for the second portion of the redundancy versionas part of the primary version.
 30. The method of claim 26, furthercomprising selecting a transmission strategy at least partially based ona data reception condition indication of a transmission, the datareception condition indication received from a mobile device.
 31. Themethod of claim 30, wherein the transmission strategy specifies at leastone of a number of redundancy versions to be transmitted, timinginformation for sending the redundancy version relative to the primaryversion, and coding schemes for encoding the primary version and theredundancy version.
 32. The method of claim 26, further comprisingchanging a frequency of the second carrier in response to a high errorrate.
 33. The method of claim 26, further comprising: transmitting afirst portion of a second redundancy version of the information via afourth carrier; and transmitting a second portion of the secondredundancy version of the information via a fifth carrier; wherein thesecond redundancy version is encoded using a third encoding scheme,wherein the first portion of the second redundancy version and thesecond portion of the second redundancy version are transmittedsubstantially simultaneously with the first portion of the redundancyversion and the second portion of the redundancy version.
 34. Anapparatus for providing redundancy for error recovery in multi-carrierwireless communications, the apparatus comprising: means for generatinga primary version of information for transmission via a first carrier;means for generating a first portion of a redundancy version of theinformation for transmission via a second carrier; means for generatinga second portion of the redundancy version of the information fortransmission via a third carrier, wherein the first portion and thesecond portion are transmitted after transmission of the primary versionis completed and wherein the redundancy version is transmitted inresponse to encoding the primary version; and means for encoding theprimary version using a first encoding scheme and encoding theredundancy version using a second encoding scheme, wherein the firstportion of the redundancy version and the second portion of theredundancy version are transmitted substantially simultaneously, andwherein the first portion of the redundancy version and the secondportion of the redundancy version are transmitted in response totransmitting the primary version; wherein decoding the primary version,the first portion and the second portion are configured to be decodedupon reception, wherein the first portion is configured to be combinedwith the primary version, with the second portion, or with the primaryversion and the second portion based on a combination scheme; whereinthe combination scheme comprises selective soft combining and whereinthe primary version, the first portion, or the second portion is furtherconfigured to be discarded without being combined.
 35. The apparatus ofclaim 34, further comprising means for transmitting the primary version,the first portion, and the second portion.
 36. The apparatus of claim35, further comprising means for transmitting a carrier mapping for thefirst portion and for the second portion of the redundancy version viaan out-of-band control channel.
 37. A communication device for providingredundancy for error recovery in multi-carrier wireless communications,the communication device comprising: a processor configured to generatea primary version of information for transmission via a first carrier,to generate a first portion of a redundancy version of the informationfor transmission via a second carrier, and to generate a second portionof the redundancy version of the information for transmission via athird carrier, wherein the first portion and the second portion aretransmitted substantially simultaneously, wherein the first portion andthe second portion are transmitted after transmission of the primaryversion is completed, and wherein the first portion and the secondportion are transmitted in response to transmitting the primary version;and an encoder configured to encode the primary version using a firstencoding scheme and to encode the redundancy version using a secondencoding scheme; wherein decoding the primary version, the first portionand the second portion are configured to be decoded upon reception,wherein the first portion is configured to be combined with the primaryversion, with the second portion, or with the primary version and thesecond portion based on a combination scheme; wherein the combinationscheme comprises selective soft combining and wherein the primaryversion, the first portion, or the second portion is further configuredto be discarded without being combined.
 38. The communication device ofclaim 37, further comprising a transmitter configured to transmit theprimary version, the first portion, and the second portion.
 39. Thecommunication device of claim 38, wherein the transmitter, theprocessor, and the encoder are included in a mobile device.
 40. Thecommunication device of claim 38, wherein the transmitter is configuredto transmit a carrier mapping for the first portion of the redundancyversion and for the second portion of the redundancy version via anout-of-band control channel.
 41. The communication device of claim 37,wherein the encoder is configured to encode a carrier mapping for thefirst portion of the redundancy version and for the second portion ofthe redundancy version as part of the primary version.
 42. A computerprogram product for providing redundancy for error recovery inmulti-carrier wireless communications, the computer program productcomprising: a non-transitory computer readable medium comprising: codefor causing a transmitter to transmit a primary version of informationvia a first carrier; code for causing the transmitter to transmit afirst portion of a redundancy version of the information via a secondcarrier; code for causing the transmitter to transmit a second portionof the redundancy version of the information via a third carrier,wherein the first portion and the second portion are transmittedsubstantially simultaneously, wherein the first portion and the secondportion are transmitted after transmission of the primary version iscompleted, and wherein the first portion and the second portion aretransmitted in response to transmitting the primary version; and codefor causing an encoder to encode the primary version using a firstencoding scheme and to encode the redundancy version using a secondencoding scheme; wherein decoding the primary version, the first portionand the second portion are configured to be decoded upon reception,wherein the first portion is configured to be combined with the primaryversion, with the second portion, or with the primary version and thesecond portion based on a combination scheme; wherein the combinationscheme comprises selective soft combining and wherein the primaryversion, the first portion, or the second portion is further configuredto be discarded without being combined.
 43. The computer program productof claim 42, further comprising code for causing the transmitter totransmit the primary version, the first portion, and the second portion.44. The computer program product of claim 43, further comprising codefor causing the transmitter to transmit a carrier mapping for the firstportion of the redundancy version and for the second portion of theredundancy version via an out-of-band control channel.
 45. The computerprogram product of claim 44, further comprising code for causing theencoder to encode a carrier mapping for the first portion of theredundancy version and for the second portion of the redundancy versionas part of the primary version.
 46. A method of providing redundancy forerror recovery in multi-carrier wireless communications, the methodcomprising: during a first transmission time period: transmitting afirst primary version of first information; transmitting a first portionof a first redundancy version of the first information; and transmittinga second portion of the first redundancy version of the firstinformation; wherein the first primary version, the first portion of thefirst redundancy version and the second portion of the first redundancyversion are transmitted substantially simultaneously; and during asecond transmission time period: transmitting a second primary versionof second information; transmitting a first portion of a secondredundancy version of the second information; and transmitting a secondportion of the second redundancy version of the second information;wherein the first portion of the second redundancy version and thesecond portion of the second redundancy version are transmittedsubstantially simultaneously and after transmission of the secondprimary version is completed; wherein decoding the primary version, thefirst portion and the second portion are configured to be decoded uponreception, wherein the first portion is configured to be combined withthe primary version, with the second portion, or with the primaryversion and the second portion based on a combination scheme; whereinthe combination scheme comprises selective soft combining and whereinthe primary version, the first portion, or the second portion is furtherconfigured to be discarded without being combined.
 47. The method ofclaim 46, wherein the first portion of the second redundancy version andthe second portion of the second redundancy version are transmitted inresponse to transmitting the second primary version.
 48. The method ofclaim 46, wherein the first primary version is encoded using a firstencoding scheme and the first redundancy version is encoded using asecond encoding scheme, wherein the first encoding scheme and the secondencoding scheme belong to a first encoding scheme family, wherein thesecond primary version is encoded using a third encoding scheme and thesecond redundancy version is encoded using a fourth encoding scheme, andwherein the third encoding scheme and the fourth encoding scheme belongto a second encoding scheme family.
 49. An apparatus for providingredundancy for error recovery in multi-carrier wireless communications,the apparatus comprising: means for generating a first primary versionof first information, a first portion of a first redundancy version ofthe first information, and a second portion of the first redundancyversion of the first information, wherein the first primary version, thefirst portion of the first redundancy version, and the second portion ofthe first redundancy version are transmitted substantiallysimultaneously during a first time period; means for generating a secondprimary version of second information, a first portion of a secondredundancy version of the second information, and a second portion ofthe second redundancy version of the second information, wherein thesecond primary version, the first portion of the second redundancyversion, and the second portion of the second redundancy version aretransmitted during a second time period and wherein the first portion ofthe second redundancy version and the second portion of the secondredundancy version are transmitted substantially simultaneously andafter transmission of the second primary version is completed; and meansfor encoding the first primary version, the first redundancy version,and the second redundancy version; wherein decoding the primary version,the first portion and the second portion are configured to be decodedupon reception, wherein the first portion is configured to be combinedwith the primary version, with the second portion, or with the primaryversion and the second portion based on a combination scheme; whereinthe combination scheme comprises selective soft combining and whereinthe primary version, the first portion, or the second portion is furtherconfigured to be discarded without being combined.
 50. The apparatus ofclaim 49, further comprising means for transmitting the first primaryversion, the first portion of the first redundancy version, the secondportion of the first redundancy version, the second primary version, thefirst portion of the second redundancy version, and the second portionof the second redundancy version, wherein the first portion of thesecond redundancy version and the second portion of the secondredundancy version are transmitted in response to transmitting thesecond primary version.
 51. The apparatus of claim 49, wherein the firstprimary version is encoded using a first encoding scheme and the firstredundancy version is encoded using a second encoding scheme, whereinthe first encoding scheme and the second encoding scheme belong to afirst encoding scheme family, wherein the second primary version isencoded using a third encoding scheme and the second redundancy versionis encoded using a fourth encoding scheme, and wherein the thirdencoding scheme and the fourth encoding scheme belong to a secondencoding scheme family.
 52. A communication device for providingredundancy for error recovery in multi-carrier wireless communications,the communication device comprising: a processor configured to generatea first primary version of first information, a first portion of a firstredundancy version of the first information, and a second portion of thefirst redundancy version of the first information, wherein the firstprimary version, the first portion of the first redundancy version, andthe second portion of the first redundancy version are transmittedsubstantially simultaneously during a first time period, the processorfurther configured to generate a second primary version of secondinformation, a first portion of a second redundancy version of thesecond information, and a second portion of the second redundancyversion of the second information, wherein the second primary version,the first portion of the second redundancy version, and the secondportion of the second redundancy version are transmitted during a secondtime period and wherein the first portion of the second redundancyversion and the second portion of the second redundancy version aretransmitted substantially simultaneously and after transmission of thesecond primary version is completed; and an encoder configured to encodethe first primary version using a first encoding scheme, to encode thefirst redundancy version using a second encoding scheme, to encode thesecond primary version using a third encoding scheme, and to encode thesecond redundancy version using a fourth encoding scheme; whereindecoding the primary version, the first portion and the second portionare configured to be decoded upon reception, wherein the first portionis configured to be combined with the primary version, with the secondportion, or with the primary version and the second portion based on acombination scheme; wherein the combination scheme comprises selectivesoft combining and wherein the primary version, the first portion, orthe second portion is further configured to be discarded without beingcombined.
 53. The device of claim 52, further comprising a transmitterconfigured to transmit the first primary version, the first portion ofthe first redundancy version, the second portion of the first redundancyversion, the second primary version, the first portion of the secondredundancy version, and the second portion of the second redundancyversion, wherein the first portion of the second redundancy version andthe second portion of the second redundancy version are transmitted inresponse to transmitting the second primary version.
 54. The device ofclaim 52, wherein the first primary version is encoded using a firstencoding scheme and the first redundancy version is encoded using asecond encoding scheme, wherein the first encoding scheme and the secondencoding scheme belong to a first encoding scheme family, wherein thesecond primary version is encoded using a third encoding scheme and thesecond redundancy version is encoded using a fourth encoding scheme, andwherein the third encoding scheme and the fourth encoding scheme belongto a second encoding scheme family.
 55. A computer program product forproviding redundancy for error recovery in multi-carrier wirelesscommunications, the computer program product comprising: anon-transitory computer readable medium comprising: code for causing atransmitter to transmit a first primary version of first information, afirst portion of a first redundancy version of the first information,and a second portion of the first redundancy version of the firstinformation, wherein the first primary version, the first portion of thefirst redundancy version, and the second portion of the first redundancyversion are transmitted substantially simultaneously during a first timeperiod; code for causing a transmitter to transmit a second primaryversion of second information, a first portion of a second redundancyversion of the second information, and a second portion of the secondredundancy version of the second information, wherein the second primaryversion, the first portion of the second redundancy version, and thesecond portion of the second redundancy version are transmitted during asecond time period and wherein the first portion of the secondredundancy version and the second portion of the second redundancyversion are transmitted substantially simultaneously and aftertransmission of the second primary version is completed; and code forcausing an encoder to encode the first primary version using a firstencoding scheme, to encode the first redundancy version using a secondencoding scheme, to encode the second primary version using a thirdencoding scheme, and to encode the second redundancy version using afourth encoding scheme; wherein decoding the primary version, the firstportion and the second portion are configured to be decoded uponreception, wherein the first portion is configured to be combined withthe primary version, with the second portion, or with the primaryversion and the second portion based on a combination scheme; whereinthe combination scheme comprises selective soft combining and whereinthe primary version, the first portion, or the second portion is furtherconfigured to be discarded without being combined.
 56. The computerprogram product of claim 55, wherein the first portion of the secondredundancy version and the second portion of the second redundancyversion are transmitted in response to transmitting the second primaryversion.
 57. The computer program product of claim 55, wherein the firstencoding scheme and the second encoding scheme belong to a firstencoding scheme family and wherein the third encoding scheme and thefourth encoding scheme belong to a second encoding scheme family.
 58. Amethod of error recovery in multi-carrier wireless communications, themethod comprising: receiving a primary version of information encodedwith a first encoding scheme, the primary version being received via afirst carrier; receiving a first portion of a redundancy version of theinformation encoded using a second encoding scheme, the first portionbeing received via a second carrier; receiving a second portion of theredundancy version of the information encoded using the second encodingscheme, the second portion being received via a third carrier; decodingthe primary version, the first portion and the second portion; andcombining, based on a combination scheme, the first portion with theprimary version, with the second portion, or with the primary versionand the second portion; wherein the combination scheme comprisesselective soft combining and wherein the primary version, the firstportion, or the second portion is further configured to be discardedwithout being combined.
 59. The method of claim 58, wherein the firstportion and the second portion are configured to be receivedsubstantially simultaneously after reception of the primary version iscompleted.
 60. The method of claim 58, wherein the primary version, thefirst portion, and the second portion are configured to be receivedsubstantially simultaneously.
 61. The method of claim 1, wherein atleast one of the first portion and the primary version or the firstportion and the second portion is configured to be combined in responseto reception conditions being below a threshold.
 62. The method of claim1, wherein the combination scheme comprises soft combining and whereinthe first portion of the redundancy version, the second portion of theredundancy version, and additional redundancy versions are configured tobe combined using a statistical process.
 63. The method of claim 58,wherein the combination scheme is configured to be changed in responseto a reception error rate being higher than a threshold.
 64. The methodof claim 1, further comprising receiving a data reception conditionindication of a transmission from a receiver.
 65. An apparatus for errorrecovery in multi-carrier wireless communications, the apparatuscomprising: means for receiving a primary version of information encodedwith a first encoding scheme, the primary version being received via afirst carrier; means for receiving a first portion of a redundancyversion of the information encoded using a second encoding scheme, thefirst portion being received via a second carrier; means for receiving asecond portion of the redundancy version of the information encodedusing the second encoding scheme, the second portion being received viaa third carrier; means for decoding the primary version, the firstportion and the second portion; and means for combining, based on acombination scheme, the first portion with the primary version, with thesecond portion, or with the primary version and the second portion;wherein decoding the primary version, the first portion and the secondportion are configured to be decoded upon reception, wherein the firstportion is configured to be combined with the primary version, with thesecond portion, or with the primary version and the second portion basedon a combination scheme; wherein the combination scheme comprisesselective soft combining and wherein the primary version, the firstportion, or the second portion is further configured to be discardedwithout being combined.
 66. The apparatus of claim 65, wherein the firstportion and the second portion are configured to be receivedsubstantially simultaneously after reception of the primary version iscompleted.
 67. The apparatus of claim 65, wherein the primary version,the first portion, and the second portion are configured to be receivedsubstantially simultaneously.
 68. The apparatus of claim 65, wherein atleast one of the first portion and the primary version or the firstportion and the second portion is configured to be combined in responseto reception conditions being below a threshold.
 69. A communicationdevice for error recovery in multi-carrier wireless communications, thecommunication device comprising: a processor configured to receive aprimary version of information encoded with a first encoding scheme, theprimary version being received via a first carrier, a first portion of aredundancy version of the information encoded using a second encodingscheme, the first portion being received via a second carrier, a secondportion of the redundancy version of the information encoded using thesecond encoding scheme, the second portion being received via a thirdcarrier; and a decoder configured to decode the primary version, thefirst portion and the second portion, wherein the processor is furtherconfigured to combine, based on a combination scheme, the first portionwith the primary version, with the second portion, or with the primaryversion and the second portion; wherein the combination scheme comprisesselective soft combining and wherein the primary version, the firstportion, or the second portion is further configured to be discardedwithout being combined.
 70. The communication device of claim 69,wherein the first portion and the second portion are configured to bereceived substantially simultaneously after reception of the primaryversion is completed.
 71. The communication device of claim 69, whereinthe primary version, the first portion, and the second portion areconfigured to be received substantially simultaneously.
 72. Thecommunication device of claim 69, wherein at least one of the firstportion and the primary version or the first portion and the secondportion is configured to be combined based on the combination scheme inresponse to reception conditions being below a threshold.
 73. A computerprogram product for error recovery in multi-carrier wirelesscommunications, the computer program product comprising: anon-transitory computer readable medium comprising: code for causing acomputer to receive a primary version of information encoded with afirst encoding scheme, the primary version being received on a firstcarrier; code for causing the computer to receive a first portion of aredundancy version of the information encoded using a second encodingscheme, the first portion being received on a second carrier; code forcausing the computer to receive a second portion of the redundancyversion of the information encoded using the second encoding scheme, thesecond portion being received on a third carrier; code for causing thecomputer to decode the primary version, the first portion and the secondportion; and code for causing the computer to combine, based on acombination scheme, the first portion with the primary version, with thesecond portion, or with the primary version and the second portionwherein the combination scheme comprises selective soft combining andwherein the primary version, the first portion, or the second portion isfurther configured to be discarded without being combined.
 74. Thecomputer program product of claim 73, wherein the primary version, thefirst portion, and the second portion are configured to be receivedsubstantially simultaneously.
 75. The computer program product of claim73, wherein the first portion and the second portion are configured tobe received substantially simultaneously after reception of the primaryversion is completed.
 76. The computer program product of claim 73,wherein the first portion of the redundancy version, the second portionof the redundancy version, and the additional redundancy versions areconfigured to be combined using a statistical process.